John L. Roseberry

Assessing the Suitability of Landscapes for Northern Bobwhite

Widespread declines of northern bobwhite (Colinus virginianus) populations may reflect habitat alteration at both site and landscape level. To investigate the latter, we quantified landscape composition and pattern throughout Illinois (>145,900 km 2 ) using classified satellite imagery and FRAGSTATS software. We then compared landscape structure with indexes of northern bobwhite abundance using county-level harvest and North American Breeding Bird Survey (BBS) data. Analyses at both scales suggested bobwhite were primarily associated with diverse, patchy landscapes that contained moderate amounts of grassland and row crops and abundant woody edge. These findings were used to develop a PATREC model to identify and map Illinois landscapes potentially suitable for bobwhite. Whether or not such areas actually support good bobwhite populations depends upon site conditions generally not discernable by remote sensing. Nevertheless, knowledge of the extent and distribution of potentially suitable landscapes can enhance and focus management efforts.

Bobwhite Population Responses to Exploitation: Real and Simulated

A population model for bobwhite quail (Colinus virginianus) was used to evaluate harvest strategies via simulation. Highest sustained yields were obtained from a simulated annual harvest rate of 55%, which reduced standing fall densities by 28%. A harvest regime of 40-45% (including crippling loss) seemed most appropriate as nearly comparable returns were realized with considerably less population reduction. Compensatory adjustments to exploitation were afforded by the nonadditive numerical relationship between hunting and nonhunting losses plus the density-dependent nature of seasonal mortality and reproductive rates. These mechanisms interacted to cushion, but not completely absorb, the impact of hunting on standing densities. Successful population adjustment to exploitation became progressively more difficult as harvesting intensified because the rate of recruitment necessary to maintain equilibrium increased exponentially with increased fall to spring mortality. J. WILDL. MANAGE. 43(2):285-305 Despite the bobwhites widespread popularity as a game bird, the effects of varying intensities of harvest on standing densities and long-term yields are not well documented. There is not a consensus optimum harvest rate nor criteria for defining one. Some apparently consider it virtually impossible to overshoot quail under natural conditions (discussions following Mosby and Overton 1950:353355, and Swank and Gallizioli 1954:296297)-a view not shared by Errington and Hamerstrom (1936:422). Recommended harvest rates in the literature range from under 40 to 70% of fall densities (Errington and Hamerstrom 1935, 1936:423, Baumgartner 1944:259, Rosene 1969:206207, Vance and Ellis 1972:169). Hickey (1955a:374) reasoned that monogamous birds could probably tolerate a hunting kill equivalent to about 1/2 of their annual

Factors influencing efficiency of white-tailed deer harvest in Illinois

We sought to determine the influences of landscape pattern and human habitation on deer vulnerability to harvest over relatively large geographic scales. We defined deer harvest efficiency as the proportion of the population taken per unit of effort, and computed it for each Illinois county using model-derived population estimates combined with actual hunter harvest and effort data. We then compared county-level efficiency indices with corresponding amounts and spatial characteristics of forest patches derived from classified satellite imagery. We also compared harvest efficiency with relative human occupation of the landscape based on census data. Deer were more susceptible to harvest in counties with small amounts of highly fragmented forest cover than in more heavily and contiguously forested areas. Harvest efficiency also was slightly higher in sparsely populated counties than in those with greater human presence. Our findings illustrate how wildlife managers can use emerging tools such as remote sensing and geographical information systems (GIS) to address management issues at appropriate geographic scales.

Influence of exurban development on hunting opportunity, hunter distribution, and harvest efficiency of white-tailed deer

Abstract Harvest efficiency for white-tailed deer (Odocoileus virginianus) primarily is dependent upon the density and distribution of hunters. Therefore, factors affecting hunter distribution (i.e., human habitations) likely will influence harvest efficiency. We compiled rural structure maps for 98 of 102 Illinois counties. Lands within 274 m of rural structures were considered a potential hunter “restriction zone”. based on Illinois hunting regulations. We determined deer-habitat composition within the restriction zone and within each county and then compared it to variations in harvest efficiency. We evaluated the influence of this zone on individual hunter distribution through an aerial survey. We evaluated hunter distances to nearest structures, densities within the restriction zone, and factors associated with hunter presence or absence. Over 4 million ha (30%) of the rural Illinois landscape falls within the potential hunter restriction zone. Restriction zone composition differed from the remainder of counties for forage and marginal habitat classes. Variables associated with the convergence of human development and deer habitat explained a major proportion of variation in harvest efficiency. As rural development increased and protected more deer habitat, harvest efficiency decreased. In areas surveyed, human dwellings reduced hunter use of surrounding areas, thus lowering hunting pressure in the hypothesized “restriction zone”. Increases in human development will make it more difficult to manage deer successfully with traditional methods. Managers will be required to identify likely areas of conflict in which nontraditional deer management would be most effective; predictive models will aid this process.

Some Morphological Characteristics of the Crab Orchard Deer Herd

Whole and dressed body weights were obtained from 1,009 white-tailed deer (Odocoileus virginianus) from Crab Orchard National Wildlife Refuge, Williamson County, Illinois. Chest girths, hindfoot lengths, lower mandible lengths, and antler dimensions were taken from somewhat smaller samples. The data were analyzed by sex and age, and relationships with body weight were established. Males generally were larger than like-aged females with respect to all measurements. Both sexes reached near-maximum size at 4.5 years of age but females matured earlier than males, especially with regard to body weight. Indices of condition (body weight and antler size) indicated that the previously unharvested Crab Orchard herd compared favorably with nearby hunted populations with the possible exception of yearling males. J. WILDL. MANAGE. 39(1):48-58 This paper describes certain morphological features of a large sample of whitetailed deer from a previously unharvested herd. Body weights, chest girths, hindfoot lengths, lower mandible lengths, and antler measurements are analyzed by sex and age classes and growth patterns are discussed. Body weights and antler measurements are used to compare general condition of the herd with that of deer in nearby hunted range. The sample was obtained during a controlled harvest to reduce herd size on Crab Orchard National Wildlife Refuge (CONWR), Williamson County, Illinois (Roseberry et al. 1969). All deer were taken from a 7,285-ha (18,000-acre) portion of the Refuge that normally is closed to hunting. The herd was first established in 1942 and has been under intensive study since 1960 by the Cooperative Wildlife Research Laboratory (CWRL) of Southern Illinois University at Carbondale. The habitat, which is considered ideal for deer (Hawkins et al. 1971), has been described previously (Autry 1967, Hawkins and Klimstra 1970). Population density prior to the January 1966 special harvest was estimated to be 1 deer/3.2 ha (1 deer/8 acres) (Autry 1967). The authors are indebted to the many graduate and undergraduate workers of the Cooperative Wildlife Research Laboratory who aided in the collection of data. We also acknowledge officials of the Crab Orchard National Wildlife Refuge and personnel of the Illinois Department of Conservation for assistance. This paper is a contribution from Project No. 15 of the Laboratory: Big Game Investigations. METHODS AND MATERIALS All harvested deer were processed at one of two check stations operated by Laboratory personnel. The animals initially were weighed 0.45 kg (1 pound) with a Viking spring balance, eviscerated, then reweighed. The maximum chest girth of all deer with rib cage intact was measured ? 0.32 cm (1 inch) with a flexible tape measure. Length of the hindfoot from hock to the tip of the longest claw was measured by the same procedure (Brohn and Robb 1955, Park and Day 1942). Antler beam diameter was measured to the nearest 1.0 mm with a vernier caliper. The beam diameter was taken 2.54 cm (1 inch) above the burr and, when possible, did not include bony protuberances (Anderson and Medin 1969). Antler length was measured ? 0.32 cm 48 J. Wildl. Manage. 39(1):1975 This content downloaded from 40.77.167.54 on Sat, 14 May 2016 06:18:18 UTC All use subject to http://about.jstor.org/terms MORPHOLOGICAL CHARACTERISTICS OF DEER * Roseberry and Klimstra 49 (s inch) with a flexible steel tape measure along the outside of the main beam from burr to tip. Length and diameter were recorded from the left beam, but the undamaged right beam was measured when the left was damaged. All antler protuberances over 2.54 cm long, excluding brow tines, were counted (as the number of antler points) on both beams. A lower mandible was removed from most animals for purposes of age determination. Age classes in this study were established on the basis of tooth eruption and wear (Severinghaus 1949). Total length of the mandible, from its most anterior point to the posterior rim of the angle of ramus (dentary length) was measured to the nearest 1.0 mm with a modified meter rule. The distance between the alveola of the anterior premolar and the corner incisor (diastema length) was measured to the nearest 0.1 mm with a vernier caliper (Bergerud 1964). All data were placed on 80-column IBM cards and processed with an IBM 370/155 computer at the data processing facilities of Southern Illinois University at Carbondale.

Dynamics of an Unexploited Bobwhite Population in Deteriorating Habitat

The dynamics of an unexploited bobwhite (Colinus virginianus) population were investigated over a 9-year period in southern Illinois. Deteriorating habitat caused an 85% population decline from 136 to 21 birds per 100 hectares. Accompanying changes in demographic parameters are described. J. WILDL. MANAGE. 43(2):306-315 Since 1950, the Cooperative Wildlife Research Laboratory (CWRL) of Southern Illinois University-Carbondale has been investigating the ecology of a hunted bobwhite population near Carbondale (Roseberry and Klimstra 1972). A 2nd study was initiated in 1965 to obtain comparative data from a nearby unexploited population. Because of substantial changes in the latter areas carrying capacity for bobwhites, some planned analyses were precluded. However, the situation did provide opportunity to observe certain population phenomena under unique conditions. The purpose of this paper is to: (1) document a rapid and considerable decline in the abundance of a local unexploited bobwhite population, (2) describe the changes in various demographic parameters which accompanied this decline, and (3) attempt to identify the causes of the decline. This paper is a contribution from Project No. 1: Bobwhite Quail Life History and Population Studies, Cooperative Wildlife Research Laboratory, Southern Illinois University-Carbondale. The authors are grateful to the many graduate students and undergraduate student workers of the Laboratory who aided in censuses and nest hunting. Appreciation s ext nded to S. L. Wunderle, W. H. Nesbitt, and D. Urban for their special contributions to the project. The collaboration of personnel of the University Farms is acknowledged. STUDY AREA AND METHODS The study area was a 449-ha tract owned by Southern Illinois UniversityCarbondale in Jackson County, hereafter referred to as the SIU Farms. Farming activities were conducted by various departments within the School of Agriculture. The area was bounded on the south and west primarily by other SIU farmland and on the north and east by residential areas and the campus. Topography is gently rolling with maximum and minimum elevation 146 and 125 m, respectively. The glaciated soils are Hosmer and Stoy silt loams of moderate productivity and medium fertility. Distribution and abundance of bobwhites were determined 4 times each year (early November, late December, early February, and mid-March) by direct census. The entire area was systematically traversed by crews of 6-12 men and 1-2 trained bird dogs. Nest searching of selected areas employed methods described by Klimstra and Roseberry (1975:7). Live-trapping utilized wire traps described by Stoddard (1931:447) and baited with either grain or live decoy 1 Present address: 105-K East Ticonderoga Drive, Westerville, OH 43081. 306 J. Wildl. Manage. 43(2):1979 This content downloaded from 157.55.39.35 on Mon, 29 Aug 2016 05:16:09 UTC All use subject to http://about.jstor.org/terms BOBWHITE IN DETERIORATING HABITAT. Roseberry et al. 307 hens. Captured birds were marked with No. 1 aluminum leg bands (National Band and Tag Co., Newport, Ky.) and their sex, age, and weight were determined prior to release at the capture site. Land use and cover patterns were recorded on 1 July and 1 November of each year. Cover removal or other habitat alteration was recorded as it occurred.

Biochemical Genetics of Wild, Semi-Wild, and Game-Farm Northern Bobwhites

Horizontal starch-gel electrophoresis of selected blood proteins was used to determine levels and patterns of genetic differentiation between wild and game-farm northern bobwhites (Colinus virginianus) and to observe genetic expression in first and second filial (F, and F2) crosses. Assays of 18 enzymes and nonenzymatic proteins provided information on 19 presumptive genetic loci. Seven loci exhibited variation, though only 4 were sufficiently variable to be considered polymorphic (0.95-frequency criterion). Wild bobwhites expressed 21.1% polymorphism, compared to 10.5% in game-farm quail. Observed heterozygosity values were slightly higher in wild (0.050) than in game-farm (0.048) birds; genetic distance between the 2 types was 0.015. Although chronically poor survival of game-farm birds has been partially attributed to an inadequate genome, electrophoretically detectable genetic variation was not markedly deficient in this group. First filial offspring from a wild x game-farm cross possessed greater genetic variability than game-farm stock and were genetically more similar to wild quail. Variability was reduced in a F2 generation that was genetically similar to game-farm birds. J. WILDL. MANAGE. 52(1):138-144 Wildlife management has traditionally emphasized the manipulation of habitat and/or population density and structure (Giles 1978) but has minimized potentially useful genetic considerations (Smith et al. 1976). One area of management for which genetics has obvious application is the artificial propagation of game birds. Although not regarded as a viable means of augmenting natural populations (Kabat and Thompson 1963), stocking programs can provide recreational benefits, especially where opportunities for conventional hunting are limited (State of Ill. 1978). This management option is hampered, however, by poor survivability and lack of natural behavior characteristic of artificially-propagated birds, especially northern bobwhites (Buechner 1950, Klimstra 1975). Wildlife managers generally assume that in addition to disadvantages associated with artificial rearing, these birds inherently lack attributes needed for survival because of genetic deficiencies incurred from captive perpetuity and possibly inbreeding (Backs 1982). As a partial remedy, game agencies periodically attempt to infuse wild genes into captive stocks (Nestler and Studholme 1945). Despite the availability of electrophoretic techniques, genetic differentiation of wild and game-farm quail has not been documented, nor has the utility of introducing wild breeders into captive populations to improve the genome. We examined these areas by comparing genetic variability and levels f differentiation between wild and game-farm bobwhites, and describing the genetic expression i F, and F2 crosses. This investigation was conducted by the Coo erative Wildlife Research Laboratory, Southern Illinois University-Carbondale, and was partially financed by the Illinois Department of C servation as part of Federal Aid Project W-93-R. The support and cooperation of F. Kringer and M. S. Kern of that agency are acknowledged. A. Woolf, J. W. Bickham, N. J. Silvy, and S. M. Carr reviewed the manuscript.

Relationships between Selected Population Phenomena and Annual Bobwhite Age Ratios

Relationships between fall age ratios of bobwhites (Colinus virginianus) and certain population phenomena are discussed, based on a computer simulation and 17 years of data from the Carbondale Research Area in southern Illinois. Annual variation in the percentage of juveniles in fall populations on the study area was more strongly correlated with population change from fall to fall and spring to fall than with fall densities per se. Simulation techniques were used to demonstrate the combined effect of changes in proportions of hens successful and survival rates of juveniles and adults on relative population gains from spring to fall. Comparisons were made of the use of young:adult ratios and percentages of juveniles as indicators of these gains. Results of the simulation suggest that variation in juvenile mortality influences percent summer gain more than does variation in adult summer losses. However, the relationship between summer gains and the subsequent percentage of juveniles in the fall is altered by annual variation in adult mortality. In contrast, this relationship is not significantly changed by annual variation in juvenile mortality because the latter exerts an almost equal influence on both relative productivity and fall age ratios. Finally, the relationship between productivity and the proportion of juveniles in the fall is curvilinear, whereas the ratio of juveniles per adult is linearly responsive to productivity, making the latter a preferable index of breeding success. J. WILDL. MANAGE. 38(4):665-673 Over the past 30-plus years, literally hundreds of thousands of wings from harvested bobwhites have been collected for the purpose of estimating sex and age structure of the parent populations (Rosene 1969:385386). There is not, however, unanimity among researchers as to how these data may be interpreted. Proportions of juveniles in fall populations (Pj) are considered indicative of mean annual mortality rates (Hickey 1955:343), but these age ratios do not reflect year-to-year variation in mortality unless the population is stable (Marsden and Baskett 1958:415). More often, fall age ratios are used as indices of productivity and survival the previous summer (Leopold 1945, Speake and Haugen 1960). Age ratios have also been related to fall densities (Lay 1952:23, Reid and Goodrum 1960:244, Speake and Haugen 1960:94) and population change (Legler 1955:17). Stanford (1973:129), though, warned that high young: adult ratios are not always associated with high total production or populations as has often been assumed. Bennitt (1951:32-35), in fact, reported an inverse relationship between annual Pj and fall densities in Missouri. He believed that this negative correlation was due to the phenomenon of inversity (Errington 1945) whereby high reproductive rates (and thus high Pj) were usually associated with low breeding densities, which were often followed by low total production and low fall populations. Similarly, MacDonald (1964:6-7) concluded that highest hen:poult turkey (Meleagris gallopavo merriami) ratios came during years of lowest numbers of hens and thus did not indicate highest total productivity or fall populations. This paper attempts to clarify some of the relationships among annual Pj, young: adult ratios, relative productivity, juvenile and adult survival, population change, and fall densities using computer simulation techniques as well as 17 years of data from a hunted bobwhite population in southern Illinois. This material is a contribution from Project No. 1: Bobwhite Quail Life History J. Wildl. Manage. 38 (4):1974 665 This content downloaded from 157.55.39.186 on Tue, 12 Apr 2016 09:23:09 UTC All use subject to http://about.jstor.org/terms 666 BOBWHITE AGE RATIOS * Roseberry

Bobwhite Population Responses: A Reply

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